more companies accept BTC = more people will buy it.
why? does it make sense to buy bitcoins with fiat (often a long taking process) and then spend that bitcoins on buying something that you can pay with fiat in the first place? (and paying more in the end due to various fees)
I doubt that bitcoin will become mainstream just by market adoption, it will become mainstream when people choose to get their wages in bitcoins instead of fiat due to more trust in btc than in usd/eur etc.
More ppl will be interested in btc, they will learn about btc, buy some and in the end they will sell it.
btc will become mainstream, and we will not be special anymore